But while players have been ticked off for the slightest breaches of Wimbledon’s dress code this year, officials have conceded defeat in their attempts to uphold standards off court.

In previous years, debenture holders, who are entitled to a seat on Centre Court for each day of the tournament for five years, were issued with strict guidance on clothing.

Tickets stipulated that holders, who pay up to £50,000 for a debenture, needed to dress in a “smart but casual” fashion to be admitted to the exclusive debenture holders’ lounge. Jeans, sports shorts, collarless shirts and trainers were all banned.

But fresh regulations have now been issued, only ruling out "ripped jeans" or trainers which are dirty, allowing denim onto the most exclusive areas of Centre Court. Stalwarts of the championships have criticised the change for "detracting from the aura" of Wimbledon.

Critics claim that officials are operating a double standard, enforcing stricter rules on players but relaxing guidelines for the crowd.

The all-white dress code has been stringently applied to players this year, with claims that female players were forced to play without a bra after the All England Club even ruled out “off-white or cream” underwear. Caroline Wozniacki, the former world number one, said that checks to enforce the rule would be “creepy”.

On Sunday, several debenture holders were wearing denim. Very few wore ties and only a smattering of older ticket-holders were dressed in traditional tweed jackets and linen trousers.

Many wore baseball caps, shorts and open necked shirts with two or three buttons undone.

Seasoned debenture holders said that the demographic of the lounge had changed in recent years, with younger members – especially wealthy foreigners or those in seats paid for by corporations – taking a more liberal approach to the dress code.

As recently as 2012, the club issued new guidelines for its members, banning jeans, flip flops and short skirts in the clubhouse. Pictures were circulated to members, insisting men should wear lounge suits or tailored jackets with shirt, tie, trousers and dress shoes.

But no such standards are applied to the crowd. There is no dress code at all for the bulk of SW19’s spectators, but the All England Club said stewards would politely warn men if they took their tops off.

“The players have to conform to a dress code so I think we should, too,” said one member, who has held debenture seats for several years but declined to be named. “I think people should be casual but they should still be smart. It needs to be within reason – there shouldn’t be denim or trainers.

“You can’t impose one thing on the players and then have them look at the crowd and see people dressed any old way.

“These seats are expensive, so you expect a certain standard. I have noticed a few jeans around this year.”

Lillian Barnett, who works at the Saatchi Gallery in London and on Sunday wore a cream dress and navy blue blazer in the debenture seats, was disappointed by the looser guidelines.

“Out of respect for the sport, you should dress nicely,” she said. “When I was getting dressed this morning, I wanted to respect the vibe here.

“It is good that tennis is becoming more accessible. Back in the day, it was super elite. But [the new code] detracts from the aura of the whole event.”

Another debenture holder said the previous tighter regulations were being ignored in recent years.

“Even under the old rules, a friend of mine managed to get in wearing jeans because they were designer jeans and she had extremely smart clothes over the top,” she said. “You don’t have to wear a tie, but a lot of us like to.”

Debentures have been sold every five years since 1920. The revenue is used by the club to develop facilities. The first debentures were sold for £50 each, the equivalent of £2,000 today.

There are currently 2,500 debentures on Centre Court, raising £60 million of income for the All England Club, which was partly used to pay for the court's new roof.

Debentures are also sold for No. 1 Court.

The stipulation that players should wear predominantly white clothing only began in 1963. In 1995, the rule was amended to prohibit clothing that was not "almost entirely white".